1. Field of the Invention
The invention relates to a process for coating a glass sheet with a flexible film, in which the glass sheet and the film are brought together at an acute angle and are continuously moved, and by use of pressure along the contact line of film and glass sheet the film is preliminary bonded to the glass sheet by removal of air, and the preliminary bonded coating arrangement is finally bonded to one another by use of increased temperature and increased pressure. The phrase "glass sheets" is understood to mean transparent plates or sheets made of silicate glass or a plastic, for example, of polycarbonate. In this case, they can be monolithic plates or multilayer plates, for example, laminated glass sheets made from glass and plastic layers.
2. Discussion of the Background
It is known to coat glass sheets on one surface with a flexible plastic film. The plastic films can have different properties and be used for different purposes. For example, the flexible film can be used as splinterproof film in the case of silicate glass sheets. Such splinterproof films are calendar-coated onto the inside of motor vehicle windshields. They keep the passengers from coming in contact with the glass splinters in case of an collision. In the case of plates or sheets made from plastic the flexible films can perform the function of a layer for increasing scratch resistance.
Different processes are known for calendar-coating plastic sheets onto glass sheets. If a thermoplastic film is involved, or if the film is provided with a thermoplastic adhesive layer on the side to be bonded to the glass sheet, the coating process generally takes place in two steps: in the first step a preliminary bonding is performed while avoiding the inclusion of air, and in the second step the final bonding takes place by using increased temperature and increased pressure, for example, in a pressure autoclave.
Application of the flexible film and the preliminary bonding can take place according to the prior art with the help of a rolling process as, for example, is described in European patent 0 015 209. In this case, the glass sheet, which is to be coated, together with the film, passes between rolls, and a continuous web of the film is introduced at an acute angle to the glass sheet into the nip of a rolling device and is calendar-coated on the glass sheet. This process has proved successful but requires the existence of a comparatively extensive rolling device.
It is also known to perform the preliminary bonding of the film and glass sheet so that the layer arrangement consisting of the glass sheet and film is put in a closed container and the latter is evacuated. Such a process is described, for example, in DE-PS 24 24 085. But this known process does not allow any continuous production operation.